1. Field of the Invention
The present invention relates to a process for upgrading a hydrocarbonaceous feedstock using a particular alumina-based catalyst. In a preferred embodiment, the invention relates to a process for removing metals contaminants and sulphur from a heavy hydrocarbonaceous feed, such as crude petroleum or petroleum residuum.
It is well known that various metallic elements are found in petroleum crude oil, most commonly, iron, nickle, and vanadium. These metals are harmful when included in feedstocks used for further refining operations. For example, in hydrocracking operations the plating out of iron metals on the catalyst exterior surfaces can over a time cause interstitial plugging of the catalyst bed. Further, deposition of nickel and vanadium on the interior of catalyst causes catalyst deactivation. Thus, efficient removal of contaminants, particularly metals contaminants, from a hydrocarbonaceous feedstock is a desired goal.
2. Description of the Prior Art
Heretofore, many types of catalyst have been proposed for upgrading hydrocarbonaceous feedstocks. Generally, such catalysts have had high surface areas and relatively small pore diameters or very low surface areas combined with high percentages of macropores.
For example, U.S. Pat. No. 4,227,995 discloses a process in which a metal containing hydrocarbon feedstock is contacted with hydrogen and a material characterized by low porosity, low surface area, less than 5 m.sup.2 /g, high average pore diameter, greater than 1,000 .ANG., and a high distribution of large pores, at least 40% of pores greater than 10,000 .ANG..
U.S. Pat. No. 3,712,861 discloses the upgrading of hydrocarbons containing sulfur and metal contaminants with a catalyst containing 0.5-20 wt % metal sulfides dispersed in an alumina. The catalyst is characterized with an average pore diameter of about 278 .ANG. and a surface area of about 60-65 m.sup.2 /g.
U.S. Pat. No. 4,089,774 relates to a process for removing metal and sulfur contaminaints from residual oil fractions by contact with a catalyst comprising the sulfide of a Group VIB metal and iron group metal supported on an alumina that contains dispersed Delta and/or Theta phase alumina, the catalyst having at least 45% of its pore volume in pores 30 to 150 .ANG. in diameter, at least 10% of its pore volume in pores least than 30 .ANG. in diameter, and at least 15% of its pore volume in pores greater than 300 .ANG. in diameter.
Finally, U.S. Pat. No. 3,947,347 discloses a process for removing metalliferous contaminants from the hydrocarbon feedstock by contacting the feedstock in the presence of hydrogen with an inert particulate solid having an average pore size in the range of from 1,000 to 10,000 .ANG. and a surface area in the range of from 1 to 20 m.sup.2 /g.